The Arabidopsis HY5 gene encodes a bZIP protein that regulates stimulus-induced development of root and hypocotyl.

Plant developmental processes are controlled by both endogenous programs and environmental stimuli. As a photomorphogenetic mutant, hy5 of Arabidopsis has been isolated and characterized. Our detailed characterization has revealed that the mutant is deficient in a variety of stimulus responses, including gravitropic response and waving growth of roots, as well as light-dependent hypocotyl elongation.

A characteristic arrangement of aromatic amino acid residues in the solution structure of the amino-terminal RNA-binding domain of Drosophila sex-lethal.

The Sex-lethal (Sxl) protein from Drosophila melanogaster has two RNA-binding domains (RBDs). As the amino-terminal RBD (RBD1) of the Sxl protein exhibits low sequence homology to the typical RBDs, particularly at the putative functional residues, it was difficult to unambiguously locate the RNP1 and RNP2 motifs. Therefore, in the present study, we defined the amino and carboxy-terminal borders of the first RNA-binding domain (RBD1) of the Sxl protein by limited tryptic digestion.

Epidermal cell differentiation in Arabidopsis determined by a Myb homolog, CPC.

The roots of plants normally carry small hairs arranged in a regular pattern. Transfer DNA-tagged lines of Arabidopsis thaliana included a mutant with few, randomly distributed root hairs. The mutated gene CAPRICE (CPC) encoded a protein with a Myb-like DNA binding domain typical of transcription factors involved in animal and plant development.

Restoration of seminiferous tubular function after discontinuation of long-term gonadotropin-releasing hormone agonist administration in premature male rats.

We examined whether seminiferous tubular function develops normally after discontinuation of long-term gonadal suppression in premature male rats. Wistar male rats 4 weeks old were subjected to the injection of gonadotropin-releasing hormone (Gn-RH) agonist or normal saline solution as control for 12 weeks. The rats were sacrificed 0 and 6 weeks after discontinuation of the treatment.

An estimate of divergence time of Parazoa and Eumetazoa and that of Cephalochordata and Vertebrata by aldolase and triose phosphate isomerase clocks.

Previously we suggested that four proteins including aldolase and triose phosphate isomerase (TPI) evolved with approximately constant rates over long periods covering the whole animal phyla. The constant rates of aldolase and TPI evolution were reexamined based on three different models for estimating evolutionary distances. It was shown that the evolutionary rates remain essentially unchanged in comparisons not only between different classes of vertebrates but also between vertebrates and arthropods and even between animals and plants, irrespective of the models used.

NMR analysis of the hydrogen bonding interactions of the RNA-binding domains of the Drosophila sex-lethal protein with target RNA fragments with site-specific [3-15N]uridine substitutions.

It has been reported that a 183 residue fragment, consisting of the two RNA-binding domains (RBD1- RBD2) of the Drosophila melanogster Sex-lethal (Sxl) protein, strongly binds an oligonucleotide of the target RNA sequence (5'-GUUUUUUUUC-3') that regulates alternative splicing, and forms four or five hydrogen bonds with the imino groups of the RNA. In the present study, we used site-directed mutagenesis to improve the solubility of the didomain fragment of Sxl, and confirmed that this mutant fragment forms hydrogen bonds with the target RNA in the same manner as that of the wild-type fragment. The mutant fragment was shown to bind the cognate RNA sequences GUUUUUUUUC and AUUUUUUUUC more tightly than UUUUUUUUC.

A serine/threonine protein kinase gene isolated by an in vivo binding procedure using the Arabidopsis floral homeotic gene product, AGAMOUS.

During the course of characterizing fragments bound to an Arabidopsis floral protein AGAMOUS in vivo, a gene encoding a putative serine/threonine protein kinase was found on one of the fragments. The deduced 426 amino acid residues of the gene, named APK2a, are 65% identical to a previously reported Arabidopsis serine/threonine protein kinase, APK1a. The gene is composed of 6 exons and maps at 10 cM from the upper end of chromosome 1.

[Lipoprotein(a) concentrations and apolipoprotein(a) phenotype frequencies in cord blood of newborn infants and sera of children in Japan].

Lipoprotein(a) [Lp(a)] is considered to be an additional, independent, and largely genetically risk factor for the development of premature coronary heart disease. We measured Lp(a) levels and apo(a) phenotype in cord blood samples from 140(72 males, 68 females) Japanese newborn infants, and those in serum samples from seventy-nine normolipidemic out-patient children from the pediatrics. In the present study, we determined the relations between cord blood Lp(a) levels and apo(a) phenotypes.

Listener and context dependency in the perception of emotional aspects of infant voice.

Developmental aspects of an infant's ability to express emotions through vocalizations were studied based on perceptual rating experiments against 12 vocalization- and emotion-related reference words. Three groups of listeners, students, mothers with infants, and nursery governesses, rated 28 voice samples recorded from a male infant at 6, 9, 12 and 17 months of age, under a positive or negative context. Among three factors extracted by a factor analysis, one representing the emotional contrast of frightened/angry versus happy was found to be independent of listener group, infant age and context.

Factors involved in the activation of pre-mRNA splicing from downstream splicing enhancers.

The excision of introns with weak polypyrimidine tracts at their 3' splice sites can be enhanced by sequence elements in the downstream exon or by a downstream 5' splice site. The enhancers inside the exon do not conform to a strict consensus, but they are generally rich in purines. Here, we show that members of the family of SR proteins recognize these elements.

A human RNA helicase-like protein, HRH1, facilitates nuclear export of spliced mRNA by releasing the RNA from the spliceosome.

Because the nuclear export of mRNA occurs only after the splicing reaction is completed, intron-containing pre-mRNA does not normally appear in the cytoplasm. As a mechanism to secure this, intron-containing RNA is retained in the nucleus via formation of the spliceosome. Therefore, the process of releasing spliced mRNA from the spliceosome after completion of splicing is an essential step for triggering the nuclear export of the spliced mRNA.

A Y-box protein is a suppressor factor that decreases thyrotropin receptor gene expression.

The decanucleotides in a tandem repeat, -162 to -140 bp, are suppressor elements that decrease TSH receptor (TSHR) gene expression by different mechanisms. A factor(s) interacting with the 3'-decanucleotide compete for proteins that bind the cAMP response element, -139 to -132 bp, a constitutive enhancer necessary for efficient TSHR expression. The 5'-decanucleotide is in a CT-rich, S1 nuclease-sensitive region of the promoter; its suppressor activity has been related to its ability to bind a nonthyroid-specific protein to its coding strand.

Effects of growth hormone and insulin-like growth factor I on testosterone secretion in premature male rats.

Present study was planned to clarify the effects of GH and insulin-like growth factor I (IGF-I) on testosterone secretion using premature male rats. Forty rats were divided four groups. GH, IGF-I, both of them or normal saline solution as control were subcutaneously administered to the rats of each group for seven days from 3-week to 4-week of age.

Touch-inducible genes for calmodulin and a calmodulin-related protein are located in tandem on a chromosome of Arabidopsis thaliana.

Genes for calmodulin and calmodulin-related proteins in Arabidopsis are up-regulated by a variety of physical stimuli, which include rain, wind and touch [Braam and Davis (1990) Cell 60: 357]. We have isolated five genes for calmodulin (AtCAL1, 2, 3, 5, 6) and one gene for a calmodulin-related protein (AtCAL4) from an Arabidopsis genomic library. Touch stimulus of Arabidopsis plants induces the accumulation of mRNA transcribed from AtCAL4 and AtCAL5, but not from the other isolated genes.

Comparison of primary structures and substrate specificities of two pullulan-hydrolyzing alpha-amylases, TVA I and TVA II, from Thermoactinomyces vulgaris R-47.

Thermoactinomyces vulgaris R-47 produces two alpha-amylases, TVA I, an extracellular enzyme, and TVA II, an intracellular enzyme. Both enzymes hydrolyze pullulan to produce panose, and also hydrolyze cyclodextrins. We cloned and sequenced the TVA I gene.

Identification of the factors that interact with NCBP, an 80 kDa nuclear cap binding protein.

It has been shown that the monomethylated cap structure plays important roles in pre-mRNA splicing and nuclear export of RNA. As a candidate for the factor involved in these nuclear events we have previously purified an 80 kDa nuclear cap binding protein (NCBP) from a HeLa cell nuclear extract and isolated its full-length cDNA. In this report, in order to obtain a clue to the cellular functions of NCBP, we attempted to identify a factor(s) that interacts with NCBP.

Developmental and tissue-specific regulation of the gene for the wheat basic/leucine zipper protein HBP-1a(17) in transgenic Arabidopsis plants.

Wheat basic/leucine zipper protein HBP-1a(17) binds in vitro specifically to ACGT motif-containing cis-acting elements, such as the type I element of plant histone promoters and the G-box of hormone- and light-inducible promoters. To address the in vivo function of HBP-1a(17), we isolated and structurally analyzed the HBP-1a(17) gene and examined its expression in transgenic Arabidopsis plants. The HBP-1a(17) gene is composed of 14 exons; the basic region and leucine zipper are encoded by separate small exons, as is the case for other bZIP protein genes.

Transcriptional regulation of the Sex-lethal gene by helix-loop-helix proteins.

Somatic sex determination in Drosophila depends on the expression of Sex-lethal (Sxl), whose level is determined by the relative number of X chromosomes and sets of autosomes (X:A ratio). The first step in regulation of Sxl expression is transcriptional control from its early promoter and several genes encoding transcription factors of the helix-loop-helix (HLH) family such as daughterless (da), sisterless-b (sis-b), deadpan (dpn) and extramacrochaetae (emc) have been implicated. By the use of transfection assays and in vitro binding experiments, here we show that da/sis-b heterodimers bind several sites on the Sxl early promoter with different affinities and consequently tune the level of active transcription from this promoter.

Single strand DNA-binding proteins and thyroid transcription factor-1 conjointly regulate thyrotropin receptor gene expression.

An element, -186 to -176 base pairs (bp), in the minimal TSH receptor (TSHR) promoter binds thyroid transcription factor-1 (TTF-1) and is important for both constitutive expression and TSH/cAMP-induced negative autoregulation of the TSHR in thyroid cells. An element on the noncoding strand of the TSHR, contiguous with the 5'-end of the TTF-1 element, has single strand binding activity. It is distinct from the TTF-1 site, as evidenced by competition experiments using gel shift assays; but the association of the two elements is not random.

Genetic analysis of the structure and function of RNase P from E. coli.

A brief review of the genetic studies on ribonuclease P (RNase P) from Escherichia coli is presented. Temperature-sensitive mutants of E. coli defective in tRNA processing were isolated by screening cells which were unable to synthesize a suppressor tRNA at restrictive temperature.

Characterization of an up-stream thyroid transcription factor-1-binding site in the thyrotropin receptor promoter.

A thyroid transcription factor-1 (TTF-1)-binding element in the rat TSH receptor (TSHR) promoter, between -189 and -175 basepairs (bp), is important for both thyroid-specific expression and thyroid-specific TSH/cAMP autoregulation of the TSHR. The identification of an up-stream TTF-1-binding site and its relationship to the function of the down-stream TTF-1 element are the subjects of this report. Sequence analysis identifies a potential TTF-1 site at -878 bp; deoxyribonuclease-I footprinting shows that the -881 to -866 bp region is protected by recombinant TTF-1 protein and by nuclear extracts from FRTL-5 thyroid cells that contain TTF-1, but not by extracts from nonfunctioning FRT thyroid or Buffalo rat liver (BRL) cells, which have no TTF-1, or by Pax-8.

Aspects of splice site selection in constitutive and alternative pre-mRNA splicing.

RNA splicing is an indispensable step for expression of many eukaryotic genes. Combinations of 5' and 3' splice sites should be correctly selected in both constitutive and alternative splicing. Recent studies have revealed mechanisms of alternative splicing in some systems, in which specific regulators play vital roles in splice site selection.

The thyrotropin receptor.

This chapter has outlined the complex process required for thyroid growth and function. Both events are regulated by TSHR via a multiplicity of signals, with the aid of and requirement for a multiplicity of hormones that regulate the TSHR via receptor cross-talk: insulin, IGF-I, adrenergic receptors, and purinergic receptors. Cross-talk appears to regulate G-protein interactions or activities induced by TSH as well as TSHR gene expression.

Identification of a novel insulin-responsive element in the rat thyrotropin receptor promoter.

By transfecting TSH receptor (TSHR)-chloramphenicol acetyltransferase (CAT) chimeras into FRTL-5 thyroid cells in the presence or absence of insulin, we identify an insulin-responsive element (IRE) between -220 and -190 bp of the TSHR 5'-flanking region. The region between -220 and -192 bp is footprinted by nuclear extracts from FRTL-5 cells and, coupled to a heterologous SV40-CAT chimera, an oligonucleotide containing the protected region induces insulin responsiveness in FRTL-5 cells. FRTL-5 cell nuclear extracts form two groups of protein-DNA complexes, A and B, in gel shift assays using an oligonucleotide having the protected sequence; mutation data indicate only the A complexes are increased by exposure of FRTL-5 cells to insulin; TSH can also increase A complex formation, but the TSH action is insulin-dependent.